Astronomers detected Slowest-spinning radio pulsar

Discovery plot of PSR J0250+5854, folded at the fundamental period of 23.535 s, as inferred by the harmonically related candidates from the same observation. Note that, in the discovery observation, there was no candidate identified at the fundamental period itself. Credit: Tan et al., 2018

An international team of astronomers has discovered a new radio pulsar as part of the LOFAR Tied-Array All-Sky Survey (LOTAAS). The newly detected object, designated PSR J0250+5854, turns out to be the slowest-spinning radio pulsar known to date.

Pulsars are normally recognized as short bursts of radio emission. Radio pulsars are usually very polarized, quickly turning neutron stars with a lighthouse beam emission that creates the pulsed emission.

Astronomers led by Chia Min Tan of the Jodrell Bank Centre for Astrophysics in Manchester, UK, has found a new radio pulsar with a relatively long spin period. The detection was made in July 2017, using the LOw-Frequency Array (LOFAR) radio telescope network located mainly in the Netherlands, as part of the LOTAAS survey. LOTAAS is an all-Northern-sky survey for pulsars and fast transients at a central observing frequency of 135 MHz.

Astronomers noted, “We subsequently detected pulsations from the pulsar in the interferometric images of the LOFAR Two-meter Sky Survey, allowing for sub-arcsecond localization.”

PSR J0250+5854 has the slowest spin period when compared to any other known magnetars and X-ray dim isolated neutron stars (XDINSs). The similarity of the rotational parameters of the newly detected pulsar to the XDINSs and magnetars indicates a possible connection between them.

The researchers also found that PSR J0250+5854 has a surface magnetic field strength of 26 trillion G, an age of 13.7 million years and spin-down luminosity of 82 octillion erg/s. According to the paper, these values suggest a dipolar magnetic field configuration in this pulsar.

researchers stressed the significance of their disclosure, taking note of that it has fundamentally extended the known scope of rotation-powered pulsar periods. They added that LOTAAS has the potential in finding all the more slow spinning pulsars like PSR J0250+5854 or even with slower turn periods.

The finding is reported in a paper published September 4 on arXiv.org.